1. Field of the Invention
This invention relates generally to agricultural field marking systems, and more particularly relates to apparatus and method for planting a grain field so that certain rows of plants will grow in a pattern different from the other rows and thereby act as markers for later operations such as weed control spraying.
2. Description of the Prior Art
Feed grain crops such as oats, barley and wheat are usually planted in closely spaced rows by means of a grain drill. It has become common practice to spray the field with herbicide for weed control after the plants have emerged. Either aircraft or ground spraying equipment can be used. In either case, it is very difficult to prevent skipping and overlapping from occurring. The skips permit weeds to develop and the overlaps cause grain damage.
To minimize these problems when using aircraft, it has been necessary to use flagmen at the ends of the field or to drop paper strips from the aircraft on successive passes. When ground-type spraying equipment is used, the operator must attempt to judge the correct distance from the previous wheel tracks in the grain. The ends of some sprayer booms have been provided with powder or flour markers, but these have not been satisfactory in operation and have been too expensive and troublesome. Flagmen have also been used with ground spraying equipment. In areas of the country where sprayer booms up to 200 feet wide have been used, it has sometimes been necessary to have a man ride a motorcycle down the field at the end of the boom. This causes additional injury to the plants and still leaves the operator of the ground equipment up to 100 feet from the mark. The extra man also considerably increases the expense of the operation. In general, there is no satisfactory or economical system or method of marking a field for spraying that is available at the present time.